1. Technical Field
The present invention relates to an illuminating apparatus which illuminates an optical modulating device such as a liquid crystal light valve, and a projector having the same therein.
2. Related Art
For a first projector, there is one which collects source light from a light source lamp, enters it into one end of a rod integrator through an opening that is disposed at the center of a reflecting mirror and obtains the luminous light of a single polarization component through a polarization separation device that is disposed at the other end (see JP-A-2003202523) In this case, in reciprocating the reflected light from the polarization separation device by the reflecting mirror, the polarization direction is changed by a wave plate disposed on an optical path, and thus the light is passed through the polarization separation device.
For a second projector, there is one which collects source light emitted from a light source lamp, causes it to enter one end of a rod integrator and subjects the light emitted from the other end side to polarization conversion by a polarization conversion unit formed of a polarization beam splitter and other devices and thus obtains the luminous light having a uniform single polarization component (see FIG. 14 in JP-A-2000-56266).
For a third projector, there is one which is provided with a solid light source on the incident end face of a rod and disposed with a light valve on the output end face of the rod through a lens (JP-A-2003-262795). In this projector, the light from the solid light source is made uniform in the rod, and emitted from the output end face. The output end face directly illuminates the light valve.
However, among the projectors above, in the first projector, a half of the components that first transmit through the polarization separation device are not made uniform sufficiently.
In addition, in the second and third projectors, the rod integrator makes the luminous light uniform. Thus, the targeted uniform light cannot be achieved unless the rod integrator is made long, and the unit of an illuminating apparatus tends to be increased in size.